US 5,012,333 AGranted

Interactive dynamic range adjustment system for printing digital images

AssigneeEastman Kodak Company

InventorsHsien-Che Lee, Martin C. Kaplan, Robert M. Goodwin

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Abstract

An interactive dynamic range adjustment method for printing digital images, and an implementation system, are disclosed. The method is based on experimental findings about visual photoreceptor adaption and human visual contrast sensitivity. The system adjusts the contrast of the low-frequency component only of the image, preserving (or if one wishes, enhancing) the high-frequency image component in its contrast. The adjustment is controlled by a mapping curve which the user manipulates interactively. The simulated optical print image and the dynamic range adjusted image are displayed side by side on a monitor screen so that the user can make proper selection of parameters to achieve the desired effect. For many images, the system automatically computes good parameters and no further adjustment is needed.

Claims7

Dependent claims

An interactive dynamic range adjustment method for digital images comprising the steps of:

(a) converting an R,G,B digital image signal into luminance image signals;
(b) low pass filtering the luminance image signals to provide low frequency component luminance image signals;
(c) subtracting the low frequency component luminance image signals from the luminance image signals to provide high frequency component luminance image signals;
(d) modifying, interactively, the low frequency components of the luminance image signals by mapping through a mapping curve to a density space;
(e) recombining the modified low frequency and high frequency components of the luminance image signals of steps (c) and (d);
(f) mapping the recombined modified low and high frequency components of the luminance image signals of (e) through a paper shape curve;
(g) mapping an R,G,B digital image signals of step (a) through a paper shape curve;
(h) transforming the mapped R,G,B signals of step (g) into chrominance image signals;
(i) combining the luminance image signals of step (f) and the chrominance image signals of step (h);
and
(j) transforming the combined signals from (i) to R,G,B image signals to provide an interactively adjusted digital image.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/293,838Filed 5 Jan 1989
Granted: 30 Apr 1991
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04N 1/4072
Control or modification of tonal gradation or of extreme levels, e.g. background level: dependent on the contents of the original
H04N 1/58
Processing of colour picture signals: edge or detail enhancement; Noise or error suppression, e.g. colour misregistration correction
H04N 1/60
Processing of colour picture signals: colour correction or control
H04N 1/6011
Colour correction or control: with simulation on a subsidiary picture reproducer